If you are trying to this file and it won't open, you can try using a versatile media player like VLC Media Player or Windows Media Player .
Occasionally, files with unusual or double extensions are used to disguise malicious content. A file named video.mp4.exe , for example, might appear as an MP4 but is actually an executable. While .mp4.mp4 is less common for this, you should always verify the source before opening unknown files. Technical Background of MP4 9265599.mp4.mp4
Regardless of the name, an MP4 (MPEG-4 Part 14) is a digital container used for: If you are trying to this file and